Climate averages 1991–2020
Dorchester weather
in August.
A warm, moderately wet month: the 2nd warmest and the 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
August is a warm month in Dorchester: daytime highs average 26.3°C and nights cool to about 18.1°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 85 mm of rain on roughly 9 days, which makes August a moderately wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 54 min on an average August day.
The nearest other city in this atlas is Boston (7 km away). In August its highs average 26.6°C, about as warm as Dorchester, with 85 mm of rain.
Among the 498 cities listed in the United States, Dorchester ranks joint 423rd of 498 for the warmest August highs and joint 291st of 498 for the driest August (rainfall, lowest first). The mean August high of those 498 cities is 29.9°C; Dorchester is 3.6°C cooler than that mean.
From August to September, average highs fall by 4.1°C to 22.2°C, and monthly rainfall rises from 85 mm to 88 mm.
The annual picture
August in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Dorchester climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 1.7°C-6.3°C | -6.3°C | 94 | 10.0 | 9.59 h |
| February | 3.0°C-5.5°C | -5.5°C | 84 | 8.9 | 10.511 h |
| March | 6.7°C-1.9°C | -1.9°C | 116 | 11.1 | 11.912 h |
| April | 13.0°C3.8°C | 3.8°C | 100 | 11.0 | 13.313 h |
| May | 18.5°C9.5°C | 9.5°C | 81 | 10.6 | 14.615 h |
| June | 23.8°C15.0°C | 15.0°C | 87 | 10.1 | 15.215 h |
| July | 27.2°C18.6°C | 18.6°C | 73 | 9.6 | 14.915 h |
| August, selected | 26.3°C18.1°C | 18.1°C | 85 | 9.1 | 13.914 h |
| September | 22.2°C14.4°C | 14.4°C | 88 | 8.1 | 12.513 h |
| October | 15.9°C8.5°C | 8.5°C | 108 | 9.8 | 11.111 h |
| November | 9.9°C2.8°C | 2.8°C | 95 | 9.6 | 9.810 h |
| December | 4.6°C-2.4°C | -2.4°C | 115 | 10.8 | 9.29 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
August in nearby cities
- Boston in AugustUnited States · 7 kmHigh 26.6°C · Low 17.9°C · 85 mm rain
- Quincy in AugustUnited States · 8 kmHigh 25.8°C · Low 18.3°C · 85 mm rain
- Newton in AugustUnited States · 12 kmHigh 26.8°C · Low 18.1°C · 88 mm rain
- Lynn in AugustUnited States · 21 kmHigh 24.6°C · Low 18.3°C · 85 mm rain
- Brockton in AugustUnited States · 24 kmHigh 26.2°C · Low 18.2°C · 89 mm rain
- Lowell in AugustUnited States · 42 kmHigh 26.9°C · Low 17.6°C · 84 mm rain
- Lawrence (Massachusetts), United States in AugustUnited States · 46 kmHigh 26.9°C · Low 17.8°C · 84 mm rain
- Pawtucket in AugustUnited States · 53 kmHigh 27.2°C · Low 18.4°C · 96 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Dorchester) is explained once on the Dorchester year overview and on the Sources, method and limits page.
Boston and Quincy lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.